Obamacare's individual mandate to buy health insurance, one of the most controversial parts of the law, could stick around for a few years as part of a transition, a key senator conceded Wednesday.

Sen. John Hoeven, R-N.D., told reporters Wednesday that he believes the individual mandate will be eliminated, but the question is when.

"My sense is yes, it will go away but we are still figuring out how to make the transition," Hoeven said.

He said a Senate working group drafting its own healthcare bill, which Hoeven is a part of, hasn't made any decision on how long the mandate will stick around.

"At this point, the plan is to not keep the mandate but we are discussing how to work that into the transition," Hoeven emphasized.

One source told the Washington Examiner's "Daily on Healthcare" it could last as long as 2020.

Sen. Orrin Hatch, R-Utah, said he would like to repeal the mandate but "it all comes down to the art of the doable. There are so many ideas and so many people who love their ideas, that we just have to wait and see what happens."

The idea, which has not been finalized, is a stark contrast to the American Health Care Act that passed the House earlier this month. That bill would repeal the individual mandate immediately alongside the employer mandate that forced employers with 50 or more workers to provide healthcare.

The elimination of the mandate was a key driver in the Congressional Budget Office's estimate of 24 million people going without insurance over the next decade under the original version of the AHCA.

But the mandate is one of the most controversial parts of the healthcare law and is a big driver of Republican opposition to Obamacare.

A few hours after Hatch made his comments about the mandate, the Senate Finance Committee, which he heads, sent out a press release blasting it.

"Americans who choose not to pay the high premiums face an expensive fine for not having coverage," the statement said.